1. Field of the Invention
This invention is directed in general to a detachable power supply apparatus for use with temperature probes, electrical appliances such as frypans, deep fat fryers, cookers and the like, and in particular to a magnetically attachable "break-away" power supply apparatus.
2. Description of the Related Art
Detachable power supply devices are well-known. For example, detachable temperature probes with a power supply cord fixedly attached thereto have long been used with a variety of electrical appliances including cookers, fryers, skillets, fondues, woks, corn poppers and the like. Conventional detachable temperature probes typically include a central control housing with a temperature probe extending therefrom, and a power supply cord fastened to and extending from an opposite end thereof. U.S. Pat. Nos. 2,856,489, 2,926,230, and 3,019,320 all disclose detachable thermostatic control devices including a male probe which can be removably attached to an electrical appliance by insertion into a female receiver thereof. The primary advantage of such devices is the ability to separate the probe from the appliance, allowing the appliance to be fully immersed in water for cleaning.
Detachable temperature probes require that continuous, intimate contact be maintained between the male temperature probe and the appliance's female receiver to accurately control the appliance's working temperature. For example, current Underwriters Laboratories, Inc..RTM. ("UL") STANDARDS 1083 (33.1) and (33.2) require that a detachable temperature probe attached to an appliance be capable of withstanding a separation force of 35 lbf. (156 N) at any angle for one minute.
The desire for maintaining intimate contact between an appliance and its temperature probe has compromised safety. Each year a substantial number of accidents occur, for example when a small child inadvertently trips over the probe's power cord and overturns the appliance, or when the power cord is sharply or forcefully disturbed in other ways causing the appliance to tip, overturn, or move in such a way that the contents of the appliance are spilled. Such accidents can result in serious injury, particularly when the appliance contains hot oil, boiling water, or the like. Further, studies have shown that many of these accidents occur when the probe's power cord is extended and kicked or pulled at a ninety-degree angle (90.degree.) thereto (e.g. from the side). Of course, these accidents could be prevented or reduced if, upon being kicked, pulled or otherwise forcefully disturbed, the power cord became separated from the probe without disturbing the appliance.
Indeed, UL recently addressed this issue with respect to certain appliances in its STANDARDS 1083 (36A, effective May 30, 2001) which requires that the force required to separate the detachable power supply cord from the appliances covered by the standard shall be at least 5 percent less than the force required to overcome the static friction of the appliance on a surface.
A need thus exists to provide a safe, convenient, reliable detachable power supply apparatus for use with appliances, and particularly for use with temperature probes and the like.